feat: outil de chiffrement/déchiffrement CSV pour Amadea

AES-256-GCM, gestion de clés (aléatoire ou mot de passe Argon2id),
détection automatique des colonnes Symbolic, cross-compile Windows.
100k lignes × 3 champs en ~0.14s.

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

Cargo.toml

@@ -0,0 +1,19 @@
+[package]
+name = "cryptage"
+version = "1.0.0"
+edition = "2021"
+description = "Chiffrement/déchiffrement de fichiers CSV pour Amadea"
+
+[dependencies]
+aes-gcm = "0.10"
+argon2 = "0.5"
+base64 = "0.22"
+clap = { version = "4", features = ["derive"] }
+rand = "0.8"
+rpassword = "7"
+
+[profile.release]
+opt-level = 3
+lto = true
+strip = true
+codegen-units = 1